1. Field of the Invention
This invention relates to a fuel supply device for an internal combustion engine which supplies fuel to both an intake manifold of an internal combustion engine, particularly a side feeding type or a bottom feeding type injector, and also a fuel delivery pipe in which the injector is integrated.
2. Discussion of the Background
In a top feeding type injector, as described in, for example, Japanese Examined Utility Model Publication Nos. 23580/1988, 39904/1989, or 16064/1990, fuel vapor is produced by heat generated by the injector. As a result, fuel pressure is lowered, and a predetermined quantity of fuel is vaporized and therefore cannot be injected. To improve this problem, for instance, as described in Japanese Unexamined Patent Publication No. 35077/1989, a side feeding type or a bottom feeding type injector has been developed and reduced to practice.
Irrespective of the injectors of these types, reducing operational sound of the injector, for the purpose of promoting a noise-free vehicle, becomes a problem of in this field of technology that is commonly addressed. In the side feeding type injector, as shown in FIG. 4, the radiation or the propagation of the operational sound is prevented by interposing the elastic body 3 of a gummy material or the like between the injector 1 and the cap 4 that fixes the injector 1 to a fuel body.
Furthermore, in recent times, complying with pluralization of intake valves for an internal combustion engine, a multi-injection hole type injector which can inject fuel towards respective intake valves for a single cylinder, has been reduced to practice. Irrespective of the number of the intake valves, the multi-injection hole type injector is adopted for the purpose of a measure for deposit (blocking by dirt) of the injector. When the multi-injection hole type injector is utilized, it is necessary to position the direction of the injection holes with respect to the intake valve of the engine, that is, with respect to the intake manifold. This necessity is common to any cases of the top feeding type, the side feeding type, and the bottom feeding type injectors.
However, as for the positioning or centering of the rotational direction of the injector at the axis of the injector, a method is adopted in which the injector is inserted to a fuel body having a plane portion as a guide. However, the plane portion becomes a transmission path of the operational sound of the injector. As a result, a noise free vehicle cannot be achieved.